The active ingredients of this invention, (1-[2-(dimethylamino)-1-(4-methoxyphenyl)ethyl]cyclohexanol), its analogues or therapeutically acceptable salts thereof, are known generally as venlafaxine. These ingredients are disclosed in U.S. Pat. No. 4,535,186 (Husbands et al.) and have been previously reported to be useful as an antidepressant. U.S. Pat. No. 4,535,186 teaches the production of venlafaxine and its analogues and is incorporated herein by reference.
Venlafaxine has been shown to be a potent inhibitor of monoamine neurotransmitter uptake, a mechanism associated not only with demonstrated clinical antidepressant activity, but also with reproductive function by affecting indirectly the hypothalamic-pituitary-ovarian axis. Due to its novel structure, venlafaxine has a mechanism of action different from other available antidepressants, such as the tricyclic antidepressants desipramine, nortriptyline, protriptyline, imipramine, amitryptyline, trimipramine, and doxepin and different from the serotonin reuptake inhibitors (SRIs), e.g. fluoxetine, sertraline and paroxetine.
It is believed that venlafaxine's mechanism of action is related to potent inhibition of the uptake of the monoamine neurotransmitters serotonin and norepinephrine. To a lesser degree, venlafaxine also inhibits dopamine reuptake, but it has no inhibitory activity on monoamine oxidase. O-desmethylvenlafaxine, venlafaxine's major metabolite in humans, exhibits a similar pharmacologic profile. However, venlafaxine's ability to inhibit norepinephrine and serotonin (5-HT) uptake has been predicted to have an effect not just on depression but also on reproductive function through its neurotransmitter effects on the hypothalamic-pituitary-ovarian (HPO) axis.